Joomla™ is one of the most popular free and open source CMS php/mysql software scripts that allows you to make powerful dynamic content websites without special knowledge and advanced technical skills.
In fact, Joomla's huge success is due to the quick and easy install and start-up process that will create a default website in minutes. It's fairly intuitive administration area does require some leraning and can quickly be used to modify the existing sample content or to add new content to your website.
The Joomla trademark and logistics are supported by a non-profit organization named OpenSourceMatters and its ecosystem is powered by many individual websites at the joomla.or domain.
There are thousands of third-party Joomla extensions available on the Joomla extensions directory.